Hi @fasttech ,
AFAIK, this can be done only through Reverse Proxy (you have only one public IP and you must publish to the Web different domains (www, webmail), NOT ALIASES, hosted on the same machine, with the same port (80, 443).
Of course, maybe I’m wrong.
When I have looked for MS ISA Server replacement (ISA/Forefront TMG can do Reverse Proxy), I read on a forum that you need another Linux Machine to do Reverse Proxy if your Linux Firewall/Router can’t do that.
Endian and Sophos can do Reverse Proxy from UI but only for paid versions.
I ask for this feature for a long time and for many, many times, but …
Apache can do Reverse Proxy but I don’t know how.
I think that if Apache is a part of NS, this can be done on the same machine.
I read some docs from Apache website but I’m not good enough to make this.
http://www.apachetutor.org/admin/reverseproxies
https://httpd.apache.org/docs/2.4/mod/mod_proxy.html
EDIT:
@Hunv just published here:
Proposal for ns7 VirtualHost page
about this.